Pin tool assemblies for friction stir welding and apparatus and methods including the same

Abstract

Pin tool assemblies for friction stir welding and apparatus and methods that include the pin tool assemblies. The pin tool assemblies include an outer member, an inner member, and a stop. The outer member includes an inner surface that defines an elongate internal cavity and an external shoulder that includes an opening to the elongate internal cavity. The inner member includes a welding end, extends at least partially within the elongate internal cavity, and projects from the opening such that the welding end is external the elongate internal cavity. The pin tool assembly is configured to permit motion of the inner member relative to the outer member. The stop defines a plurality of stop configurations. Each of the stop configurations restricts motion of the inner member relative to the outer member in a stop direction to define a corresponding stop distance between the welding end and the external shoulder.

The invention claimed is: 
     
       1. A pin tool assembly for a friction stir welding apparatus, the assembly comprising:
 an outer member including an inner surface that defines an elongate internal cavity, wherein the outer member further includes an external shoulder, and further wherein the external shoulder includes an opening to the elongate internal cavity; 
 an inner member that includes a welding end, wherein the inner member extends at least partially within the elongate internal cavity and projects from the opening such that the welding end is external the elongate internal cavity, and further wherein the pin tool assembly is configured to permit motion of the inner member relative to the outer member to vary a distance between the welding end and the external shoulder; and 
 a stop that extends at least partially within the elongate internal cavity and defines a plurality of stop configurations, wherein each of the plurality of stop configurations restricts, within the elongate internal cavity, the motion of the inner member relative to the outer member in a stop direction and defines a corresponding stop distance between the welding end and the external shoulder. 
 
     
     
       2. The assembly of  claim 1 , wherein the plurality of stop configurations includes a plurality of discrete stop configurations that define a corresponding plurality of different stop distances, and further wherein the plurality of discrete stop configurations includes at least two discrete stop configurations that define at least two different stop distances. 
     
     
       3. The assembly of  claim 1 , wherein the stop is a continuously variable stop that defines a continuous distribution of stop distances. 
     
     
       4. The assembly of  claim 1 , wherein the stop includes at least one of:
 (i) a retraction stop configured to limit retraction of the inner member into the elongate internal cavity and thereby to define a corresponding minimum distance between the welding end and the external shoulder; and 
 an extension stop configured to limit extension of the inner member from the opening and thereby to define a corresponding maximum distance between the welding end and the external shoulder. 
 
     
     
       5. The assembly of  claim 1 , wherein the stop includes:
 (i) an outer stop structure that is defined by a portion of the outer member that defines a portion of the elongate internal cavity; and 
 an inner stop structure that is defined by a portion of the inner member that extends within the elongate internal cavity. 
 
     
     
       6. The assembly of  claim 5 , wherein the inner member defines an inner flange that extends radially from an external surface of the inner member, and further wherein the inner stop structure includes the inner flange. 
     
     
       7. The assembly of  claim 6 , wherein the stop further includes an outer adjustment mechanism that is operatively attached to the outer member. 
     
     
       8. The assembly of  claim 7 , wherein the stop is a retraction stop, and further wherein the outer adjustment mechanism is configured to operatively contact a welding end-distal surface of the inner flange to restrict motion of the inner member within the elongate internal cavity in a retraction direction. 
     
     
       9. The assembly of  claim 7 , wherein the stop is an extension stop, and further wherein the outer adjustment mechanism is configured to operatively contact a welding end-proximal surface of the inner flange to restrict motion of the inner member within the elongate internal cavity in an extension direction. 
     
     
       10. The assembly of  claim 7 , wherein the outer adjustment mechanism includes an outer threaded bushing, wherein the outer stop structure includes an outer threaded region that extends along the inner surface of the outer member, and further wherein the outer threaded bushing is configured to be threaded into the outer threaded region via rotation of the outer threaded bushing relative to the outer member. 
     
     
       11. The assembly of  claim 7 , wherein the outer adjustment mechanism includes an outer pin, wherein the outer stop structure includes a plurality of outer holes that is configured to receive the outer pin, and further wherein the outer pin is configured to be inserted into a selected one of the plurality of outer holes. 
     
     
       12. The assembly of  claim 5 , wherein the outer member defines an outer flange that extends radially inward from the inner surface of the outer member, and further wherein the outer stop structure includes the outer flange. 
     
     
       13. The assembly of  claim 12 , wherein the stop further includes an inner adjustment mechanism that is operatively attached to the inner member. 
     
     
       14. The assembly of  claim 13 , wherein the stop is a retraction stop, and further wherein the inner adjustment mechanism is configured to operatively contact a shoulder-facing surface of the outer flange to restrict motion of the inner member within the elongate internal cavity in a retraction direction. 
     
     
       15. The assembly of  claim 13 , wherein the stop is an extension stop, and further wherein the inner adjustment mechanism is configured to operatively contact a shoulder-opposed surface of the outer flange to restrict motion of the inner member within the elongate internal cavity in an extension direction. 
     
     
       16. The assembly of  claim 13 , wherein the inner adjustment mechanism includes an inner threaded bushing, wherein the inner stop structure includes an inner threaded region that extends along the external surface of the inner member, and further wherein the inner threaded bushing is configured to be threaded into the inner threaded region via rotation of the inner threaded bushing. 
     
     
       17. The assembly of  claim 13 , wherein the inner adjustment mechanism includes an inner pin, wherein the inner stop structure includes a plurality of inner holes that is configured to receive the inner pin, and further wherein the inner pin is configured to be inserted into a selected one of the plurality of inner holes. 
     
     
       18. A friction stir welding apparatus comprising:
 the pin tool assembly of  claim 1 ; 
 a drive structure configured to rotate the pin tool assembly about a longitudinal axis of the inner member; 
 an inner member translation structure configured to selectively vary the distance between the welding end of the inner member and the external shoulder of the outer member; 
 an anvil that defines an anvil surface that is opposed to the welding end of the inner member; and 
 a separation regulating structure that is configured to selectively vary a distance between the external shoulder of the outer member and the anvil surface. 
 
     
     
       19. A method of operating a friction stir welding apparatus (FSWA) that includes the pin tool assembly of  claim 1 , the method comprising:
 locating a workpiece on an anvil of the FSWA, wherein the workpiece includes a joint between two bodies to be friction stir welded together; 
 rotating the pin tool assembly of the FSWA; 
 plunging the welding end of the inner member of the pin tool assembly into the workpiece; 
 maintaining the external shoulder of the outer member of the pin tool assembly in contact with an anvil-opposed surface of the workpiece; 
 translating the welding end of the pin tool assembly along the joint to friction stir weld the two bodies together; and 
 during the translating, restricting motion of the welding end relative to the external shoulder in the stop direction with the stop, wherein the restricting includes restricting within the elongate internal cavity. 
 
     
     
       20. A method of operating a friction stir welding apparatus (FSWA) that includes the pin tool assembly of  claim 1 , the method comprising:
 determining a desired stop configuration of the plurality of stop configurations for the pin tool assembly; and 
 adjusting a stop configuration of the pin tool assembly to the desired stop configuration by changing a location of an adjustment mechanism of the pin tool assembly, wherein the desired stop configuration corresponds to a desired distance between the welding end and the external shoulder, and further wherein the changing includes modifying a relative orientation at which the inner member, within the elongate internal cavity, operatively couples to the outer member via the adjustment mechanism.